Sometimes I'm convinced that women's clothes sizes in UK high street stores are just made up.

Iona St Joseph for BuzzFeed

I can go into H&M and buy a top in a size 12 that fits, and then have to go up to a size 18 for a top in Primark because my shoulders feel like they're going to burst out in an Incredible Hulk fashion.

In order to try and demonstrate how sizes differ on the high street, I went into central Edinburgh and tried on a pair of jeans in 10 different stores. The jeans I tried on varied from too loose around the waist, to a perfect fit, to being so small that I couldn't even get them past my thighs.

I wear jeans all the time, and there are several factors that determine the perfect pair of jeans for me, mainly based around quality and cost. I find a shop that does jeans that I like and can afford, and buy them all from there until they eventually change something about them that means they either aren't as good, or just don't fit any more.

This is the first time I've tried on jeans in some of these high street stores for about 10 years, and I was actually pleasantly surprised at how many fitted. OK, so they didn't fit very well, but I could get the button done up (most of the time), so, y'know, small victories.

I'm 5'8" and wear a UK size 16 in jeans, and I like them high-waisted and skinny, so that's the size and style I've gone for in each of the shops in order to compare how much the sizes differ between brands.

It was a good job these were stretchy and I only had porridge for breakfast, or forcing the top of these jeans together would’ve have been significantly more difficult.

Topshop used to be my go-to shop for jeans, but then they seemed to stop making them out of actual denim but kept the £40 price tag. This was the first of many pairs that seemed to have a large dose of Lycra added to them.

I’m not really familiar with Marks & Spencer’s jeans selection, so thought I would try on a couple of pairs just to see if there was any difference between the two.

The first pair I tried on (on the left) were from the Limited Edition range and would’ve set me back £39.50. These were a better quality and fit than the Topshop jeans, although they did give me a mild camel toe, which no one wants from their denim.

The second pair I tried on (on the right) were from the Indigo Collection and, despite being the same size as the previous pair, I couldn’t get them done up. They would’ve set me back £22.50, so despite the fact that they didn’t fit, at least they were cheaper. The label also stated that these were "stretchy", but clearly not stretchy enough for my needs.

It was lucky the shop wasn’t busy, because I had to leave the changing room with a pair of jeans halfway up my thighs. From the poor selection of jeans in Miss Selfridge, I opted for the "authentic skinny", which had the basic ripped knees that are so hot right now.

Presumably those knee rips are for some of your leg meat to splurge out of as you try and get these over your hips. They were also classed as "super skinny", which presumably means they are jeans FOR ANTS.

If this humiliation wasn’t enough, I was mocked by a poster for crop tops as I spent 10 minutes trying to peel the denim from my calves after this picture was taken.

Despite the fact it took me a million years to actually find a pair of jeans in my size in Gap, they were a much better fit than I thought they would be.

The Gap pair were the most expensive pair of the lot at £44.95, but they were certainly the best quality and felt like they were made of *actual* denim (gasp) as opposed to being part denim, part Lycra. I was informed that I could’ve received a sweet 30% off any purchases I made just because I had tried on a pair of jeans, so if I had been searching for some new jeans, I definitely would’ve gone for these.

Sidebar: These weren’t technically skinny jeans, as the selection was so minimal I had to go for a "slim straight" pair.

I love H&M, but before I embarked on this journey of high-street changing rooms, I anticipated that its jeans would be the worst. I tried a pair on once back in the '00s and they were just such a terrible fit (in that they didn’t actually fit) that I never bothered again, so I thought we’d have another Miss Selfridge incident on our hands.

The only thing I was surprised by was the fact that I managed to get into them AND get them done up. Just.

The jeans I went for claimed to be "shaping skinny, regular waist". I’m not entirely sure what that means, apart from the fact I had to do A LOT of breathing in to get them done up.

The price tag on these bad boys was a whopping £34.99, which I thought was a ridiculous ask for such poor-quality jeans.

Primark

Iona St Joseph for BuzzFeed

Size: 16

For similar reasons to my history with H&M, I thought Primark’s jeans would be rubbish as well. I find Primark one of the worst shops on the high street for dodgy sizing, so I wasn’t holding out any hope of getting into a pair of jeans in what I consider to be my size.

I chose a pair of their "skinny premium wash" jeans (again, WTF does that even mean?), and once again, I was pleasantly surprised by the fact that I could get into the jeans, and also by the fact they actually fitted quite well. My only gripe was that they were a bit loose around the waistband, but it was nothing that a belt couldn’t sort.

I was certainly impressed with Primark’s efforts, and despite only being £13, they were far better quality than H&M’s offering.

The pair of jeans I found in Next were described as "relaxed skinny", and were slightly on the long side, but they were certainly one of the most comfortable pairs that I tried on.

I had the most faith in Marks & Spencer and Next on this trip, as they offer more sizes for bigger women than any of the other stores that I went to, and of the two, I would’ve gone for Next’s jeans over M&S.

The jeans were a good fit, and fairly roomy (although I feel this may have something to do with the relaxed fit). They were also very reasonably priced at £26, and were better quality (more denim, less Lycra) than some of the more expensive options out there.

This almost became a repeat of what shall now be known as "the Miss Selfridge fiasco" as I almost couldn’t get this pair of jeans over my derriere, but I eventually got there, so thankfully I didn’t have to waddle out of the changing room to get my picture taken.

There was a pretty poor selection of jeans in River Island – a lot of them seemed to fall under the "jegging" category – but I finally managed to find a pair of Lana jeans, which were categorised as "super skinny high waist".

At £40, these jeans were at the fairly expensive end of the spectrum, but despite the fact they didn’t actually fit me, I’d say the asking price wasn’t ridiculous as they felt like good-quality jeans.

As Debenhams is a department store, I thought it only appropriate that I try on the first pair of relevant jeans I came across, instead of rifling through each brand and trying to decide which ones to go for.

I ended up with a pair from the J by Jasper Conran range, which were the "high waist shape and lift jean". They were of the high-waisted variety, which, thankfully, has two buttons as it needed them to keep everything in.

At £45, these were another pair of high-street jeans that I would say weren’t worth the money even if they had fitted. The quality wasn’t the best, and you could certainly get something better for less.

New Look is the store at which I currently buy my jeans, but this doesn’t mean they are exempt from the list of stores I have issues with. The last time I went to buy new jeans, I tried on four pairs in the same size, some of which fitted, some of which didn’t.

The jeans I was wearing on the day were from New Look, but I went in and picked out a random pair anyway as I knew they can vary in size. I went for a low rise pair, and they definitely weren’t as good a fit as the ones I was already wearing.

Their jeans vary in price, depending on what variety you go for, but both the ones I tried on and the ones I was wearing were £22.99.

Urban Outfitters

The final retailer I tried was Urban Outfitters, but I couldn't find any jeans in my size in the whole store. As with a lot of the items in their shops, I feel like they are targeted to women of a certain size.

I do shop in Urban Outfitters occasionally, but when I have done it's been mainly tops or accessories that I've bought, and it's very much a random selection of things that fit.

BuzzFeed Life contacted Urban Outfitters for comment, but received no response.

The main things I learnt from this are that my mum was right and I definitely should try on everything before I buy it (it's just SO BORING, MUM), and also that retailers really aren't doing anything to help women out with their body image issues.

When you go into a shop knowing what size you are, and then you can't even get a pair of jeans in the size over your arse, then it's not going to make you feel great. Fortunately, most people are already aware of the differences in sizes between retailers, but it still means that trying on clothes can be incredibly disheartening.

Not only do different brands offer different sizes, many of their own items differ in size too, so how are you meant to know what size you are when shops can't even keep their own sizes consistent?

Initially I was quite anxious about being the subject of this experiment, but then I realised that I didn't actually care that much, and that I should just say yes and get on with it! I hadn't tried on jeans in most of these stores for years, so I was concerned that I would only fit into a couple of pairs, but I was pleasantly surprised.

In terms of my shopping habits, I don't think the results will really affect where I shop. All I want is a decent pair of jeans that aren't ridiculously expensive.

TL;DR: Don't bother going to buy jeans unless you absolutely have to or you feel like your self-esteem needs a good beating. BOTTOM LINE: NOWHERE IS SAFE.